Advancements in mechanical sealing apparatus

ABSTRACT

An apparatus for connecting two pipes in fluid communication is provided. The apparatus comprises a connector body configured to, in use, bridge a first and a second pipe, each pipe having a free end. It also comprises a mechanical interlock arrangement, for preventing or limiting axial movement of the connector body relative to the free ends of the first and second pipes. The apparatus also comprises a mechanical seal arrangement for providing a metal-to-metal seal between the pipes and the connector body.

FIELD OF THE INVENTION

The present invention relates to mechanical sealing apparatus and assemblies, e.g. for use in a method of connecting two pipes in fluid communication, or for connecting a pipe in fluid communication with a connector.

BACKGROUND OF THE INVENTION

There is an ongoing requirement within the oil industry to provide cost efficient and consistent methods of connecting oil pipes together in a way that minimises the risk of oil leakage.

Typically, flanged joints are used. These have a number of disadvantages. For example, flanged joints are vulnerable and can be compromised by uneven bolt tightening. Moreover, rubber seals are generally used within these joints, and often fail due to thermal degradation, as well as being at significant risk of damage and subsequent failure from bad practice when joints are assembled on site.

Flanged joints also require welding. This is time consuming during assembly, increasing down time for pipe repairs as well as presenting a fire risk. Further, amidst recent proposals for better offshore pipeline regulation and more refined safety rules covering repairs, there is a requirement to employ qualified welders to perform any repairs, which is a considerable added expense. The installation of flange joints also requires very high precision, requiring highly skilled labour for assembly, further increasing the cost of installation, repair and maintenance.

SUMMARY OF THE INVENTION

A first aspect of the invention provides an apparatus for connecting two pipes in fluid communication, the apparatus comprising a connector body configured for bridging a first and a second pipe, each pipe having a free end; a mechanical interlock arrangement, for preventing or limiting axial movement of the connector body relative to the free ends of the first and second pipes; and a mechanical seal arrangement for providing a metal-to-metal seal between the pipes and the connector body.

In normal use, the assembly serves to provide the two pipes in fluid communication and prevents undesired separation of the pipes. The mechanical interlock arrangement advantageously locks all the components together to limit axial movement, without the use of flanges or the components having to be welded together.

In exemplary embodiments, the metal-to-metal seal acts between an internal surface of the connector body and the pipes bridged by the connector body. It will be understood that a seal is required between each pipe and the connector body. A metal-on-metal arrangement provides a very strong seal, suitable for withstanding high pressures and high temperatures. A metal seal also has a high resistance to corrosion, increasing the life of the seal, especially when compared to traditional seals, such as rubber or asbestos O-rings or gaskets.

In exemplary embodiments, the mechanical seal arrangement includes a first metallic element configured to fit on a free end of a first pipe. In exemplary embodiments, the first metallic element is specifically dimensioned to fit on a pipe, for ensuring that the mechanical seal arrangement can create a strong seal, in combination with the connector body. In exemplary embodiments, the geometry of the first metallic element ensures that the first metallic element maintains concentricity with the pipe in use.

In exemplary embodiments, the mechanical seal arrangement includes a second metallic element, configured to be located between the first metallic element and an internal surface of the connector body. As such, a seal is created between the first and second metallic elements.

Advantageously, the mechanical seal arrangement is housed generally within the connector body. This greatly decreases the risk of catastrophic failure of the apparatus (e.g. a large blow out). If a component fails, there will simply be leakage of the fluid within the assembly, e.g. along a tortuous path. In most cases, it is believed that this could be easily detected, so that the problem can be attended to as soon as possible.

In exemplary embodiments, the first metallic element is an olive having a tapered portion comprising an angled surface, arranged to contact a corresponding angled surface of the second metallic element. In exemplary embodiments, the second metallic element is a sleeve, configured to encircle the two free ends of the pipes, in use. In exemplary embodiments, the two angled surfaces have different angles. In use, the olive surface abuts the sleeve surface, forming a very strong seal.

In alternative embodiments, the sleeve is integral with the connector body, such that, in use, the seal is created between engaging surfaces of the olive and the connector body.

In exemplary embodiments, the apparatus further comprises a mechanism for applying a force to the first metallic element, in order to assure a seal between a pipe and the connector body.

In exemplary embodiments, the connector body comprises one or more apertures defining a plurality of channels through a portion of the connector body, from the front surface of the connector body to a radial internal surface, the radial internal surface being located substantially adjacent the first metallic element in use. Force applying components, such as bolts, can be inserted in the channels within the connector body to apply a force to the first metallic element, to induce axial movement of the first metallic element in the direction of the second metallic element.

In exemplary embodiments, each channel comprises an internal thread such that a bolt, with a corresponding external thread, can be rotatably inserted into each channel to provide a force that acts on the first metallic element in an axial direction.

In exemplary embodiments, the mechanical seal arrangement further comprises a resilient washer arranged for sustaining the force applied on the first metallic element. In exemplary embodiments, the washer is intended to account for any variation in the force (e.g. a reduction in applied force as the bolts, or another appropriate method of applying force, loosen over time) to ensure that a strong seal is maintained between the mechanical seal arrangement and the connector body.

In exemplary embodiments, the washer is configured to be located between the radial internal surface of the connector body comprising the apertures, and the first metallic element. Advantageously, the washer protects the first metallic element from damage, such as abrasion that might otherwise occur if the force applying components contacted the first metallic element directly.

In exemplary embodiments, the mechanical interlock arrangement comprises at least one projection on an internal surface of the connector body. In such embodiments, the projection is intended for alignment with a corresponding groove on the external surface of the pipe to be inserted into the connector. In use, the projection and groove engage one another, to substantially prevent or limit axial movement of the connector body relative to the free ends of the pipes.

In exemplary embodiments, one or both of the projections on the connector body and the groove on the pipe are circumferential.

In exemplary embodiments, the connector body is provided as separate first and second parts, such that they can be brought together around the pipes, in use.

In exemplary embodiments, the connector body is split along a horizontal plane to define the first and second parts.

Advantageously, installation of the apparatus is simplified, as the first and second parts of the connector body can be brought together in a transverse direction around the remaining components of the apparatus.

In exemplary embodiments, the first and second parts of the connector body comprise bores extending in a direction perpendicular to the horizontal plane, configured to accept connecting components, in order to couple the first and second parts of the connector body to each other.

In exemplary embodiments, each bore comprises an annular surface with a plane parallel to the horizontal plane, configured to be engaged by a connecting component in use.

A second aspect of the invention provides a pipe assembly connecting two pipes in fluid communication, the assembly comprising two pipes, each having a free end, a connector body bridging the pipes; and a mechanical seal arrangement for providing a metal-to-metal seal between each pipe and the connector body.

Similarly to the first aspect of the invention, in normal use, the assembly serves to connect the two pipes in fluid communication. It will be understood that a seal is required between each pipe and the connector body. The metal-on-metal arrangement provides a very strong seal, suitable for withstanding high pressures and high temperatures. A metal seal also has a high resistance to corrosion, increasing the life of the seal, especially when compared to traditional seals, such as rubber or asbestos O-rings or gaskets.

In exemplary embodiments, the mechanical seal arrangement comprises a first metallic element and a second metallic element, the first and second metallic elements arranged to engage each other to create a metal-to-metal seal.

In exemplary embodiments, the first metallic element is an olive having a tapered portion comprising an angled surface, arranged to contact a corresponding angled surface of the second metallic element. In exemplary embodiments, the second metallic element is a sleeve, configured to fit within the connector body and encircle the two free ends of the pipes. In exemplary embodiments, the two angled surfaces have slightly different angles.

In alternative embodiments, the sleeve is integral with the connector body, such that, in use, the seal is created between engaging surfaces of the olive and the connector body.

In exemplary embodiments, the assembly further comprises a mechanism arranged to act on the first metallic element, applying a force, to induce axial movement of the first metallic element in the direction of the second metallic element.

In exemplary embodiments, the connector body comprises one or more apertures defining a plurality of channels through a portion of the connector body, from the front surface of the connector body to a radial internal surface substantially adjacent the first metallic element.

In exemplary embodiments, the assembly further comprises a resilient washer, located between the connector body and the first metallic element, to assure the force applied on the first metallic element in use.

In exemplary embodiments, a mechanical interlock arrangement is provided.

The mechanical interlock arrangement helps to prevent undesired separation of the pipes. It also greatly simplifies the installation process, as relatively little needs to be done on site to install the assembly, compared to existing methods.

In exemplary embodiments, the mechanical interlock arrangement comprises at least one projection on an internal surface of the connector body. In such embodiments, the projection is intended for alignment with a corresponding groove on the external surface of the pipe to be inserted into the connector. In use, the projection and groove engage one another, to substantially prevent or limit axial movement of the connector body relative to the free ends of the pipes.

In exemplary embodiments, one or both of the projections on the connector body and the groove on the pipe are circumferential.

In exemplary embodiments, the connector body is provided as separate first and second parts, the first and second parts having been brought together around the pipes.

In exemplary embodiments, the connector body is split along a horizontal plane to define the first and second parts.

In exemplary embodiments, the first and second parts of the connector body comprise bores extending in a direction perpendicular to the horizontal plane, configured to accept connecting components, in order to couple the first and second parts of the connector body to each other.

In exemplary embodiments, each bore comprises an annular surface with a plane parallel to the horizontal plane, configured to be engaged by a connecting component in use.

A third aspect of the invention provides a method of connecting two pipes in fluid communication, the method comprising providing two pipes, each pipe having a free end; locating a first part of a metal-to-metal seal arrangement on the free end of each pipe; and locating each free end of the pipe within a connector body having a second part of a metal-to-metal seal arrangement, such that the connector body bridges the two pipes; wherein the first and second metal-to-metal seal arrangements provide a metal-to-metal seal between a respective pipe and the connector body.

Advantageously, the method of connecting the two pipes is very simple and easily repeatable, meaning that minimal training is required to perform the method. Also, in the case of pipe repairs, downtime is greatly reduced compared to current methods, minimising the cost of any repairs. Moreover, the method avoids the need for flanges used commonly for coupling two pipes together in fluid communication.

In exemplary embodiments, the method comprises the step of applying a force to the first part of the seal arrangement, in order to assure a seal between the pipe and the connector body.

In exemplary embodiments, the method also comprises the step of providing a mechanical interlock arrangement, for preventing or limiting axial movement of the connector body relative to the pipes.

In exemplary embodiments, the mechanical interlock arrangement comprises forming a groove on an outside surface of at least one pipe and providing a projection on an internal surface of the connector body, and engaging the projection with the groove to prevent or limit axial movement of the connector body relative to the pipes.

In exemplary embodiments, the method further comprises providing a resilient washer between the connector body and the first part of the seal arrangement, for applying a force to the seal element.

A fourth aspect of the invention provides a coupling arrangement comprising a connector and a pipe, the connector having a female open end configured to receive a male free end of the pipe, the coupling arrangement further comprising a mechanical seal arrangement configured to form a metal-to-metal seal between the connector and the pipe, wherein the mechanical seal arrangement comprises a first angled surface and a second angled surface, the first and second angled surfaces being arranged to engage each other to form the metal-to-metal seal.

The coupling arrangement has multiple advantages and applications. For example, the coupling arrangement can form part of a known expansion joint without the need for any welding.

In exemplary embodiments, the mechanical seal arrangement includes a first metallic element configured to fit on the free end of the pipe, the metallic element including the first angled surface.

In exemplary embodiments, the connector comprises the second angled surface, e.g. part of a metal sleeve or other metallic element housed within the connector, or an integral part of the connector body or socket defining the female open end.

In exemplary embodiments, the first metallic element is an olive having a tapered portion comprising the first angled surface, arranged to contact the second angled surface of the connector. In exemplary embodiments, the first and second angled surfaces have different angles. In use, the first angled surface abuts the second angled surface, forming a strong seal.

In exemplary embodiments, the apparatus further comprises a mechanism for applying a force to the metallic element, in order to assure a seal between the pipe and the connector.

In exemplary embodiments, the coupling arrangement further comprises a cap, configured to encircle the pipe, the cap defining a cavity for housing the first metallic element.

In exemplary embodiments, the cap comprises one or more apertures defining a plurality of channels through a portion of the cap, from a front surface of the cap to a radial internal surface, the radial internal surface being located substantially adjacent the first metallic element in use.

Force applying components, such as bolts, can be inserted in the channels within the cap to apply a force to the first metallic element, to induce axial movement of the metallic element in the direction of the second angled surface of the connector.

In exemplary embodiments, each channel comprises an internal thread such that a bolt, with a corresponding external thread, can be rotatably inserted into each channel to provide a force that acts on the metallic element in an axial direction.

In exemplary embodiments, the mechanical seal arrangement further comprises a resilient washer arranged for sustaining the force applied on the first metallic element, the resilient washer being located within the cavity defined by the cap. In exemplary embodiments, the washer is intended to substantially account for any variation in the force (e.g. a reduction in applied force as the bolts, or another appropriate method of applying force, loosen over time) to ensure that a strong seal is maintained between the pipe and the connector.

In exemplary embodiments, the washer is configured to be located between the radial internal surface of the cap comprising the apertures, and the first metallic element. Advantageously, the washer protects the first metallic element from damage, such as abrasion that might otherwise occur if the force applying components contacted the first metallic element directly.

In exemplary embodiments, the coupling arrangement further comprises a mechanical interlock arrangement, for preventing or limiting axial movement of the connector relative to the free end of the pipe.

In exemplary embodiments, the mechanical interlock arrangement comprises a first projection on an internal surface of the cap. In such embodiments, the first projection is intended for alignment with a corresponding groove on an external surface of the pipe to be inserted into the connector. In use, the first projection and the groove on the pipe engage one another.

In exemplary embodiments, one or both of the projections and the groove are circumferential.

In exemplary embodiments the mechanical interlock arrangement further comprises a second projection on the internal surface of the cap. In such embodiments, the second projection is intended for alignment with a corresponding groove on an external surface of the connector. In use, the second projection and the groove on the connector engage one another.

In alternative embodiments, the internal surface of the cap has a thread and the external surface of the connector has a corresponding thread, such that the cap can be screwed on to the connector to prevent or limit axial movement of the connector relative to the free end of the pipe.

In exemplary embodiments, the cap comprises separate first and second parts, such that, after assembly, they encircle the pipe.

In exemplary embodiments, the cap is split along a horizontal plane to define the first and second parts.

Advantageously, installation of the coupling arrangement is simplified, as the first and second parts of the cap can be brought together in a transverse direction around the remaining components of the coupling arrangement.

In exemplary embodiments, the first and second parts of the cap comprise bores extending in a direction perpendicular to the horizontal plane, configured to accept connecting components, in order to couple the first and second parts of the cap to each other.

In exemplary embodiments, each bore comprises an annular surface with a plane parallel to the horizontal plane, configured to be engaged by a connecting component in use.

Other aspects and features of the invention will be apparent from the claims and the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a pipe assembly according to an aspect of the invention;

FIG. 2 is a cut-away perspective view of the pipe assembly of FIG. 1 through a horizontal plane, showing the components that make up the pipe assembly;

FIG. 3 is a close-up view of the pipe assembly of FIG. 1;

FIG. 4A is a perspective view of a pipe, a component of the pipe assembly of FIG. 1;

FIG. 4B is a cross-sectional view of the pipe of FIG. 4A;

FIG. 5A is a perspective view of a connector body, a component of the pipe assembly of FIG. 1;

FIG. 5B is a cross-sectional view of the connector body of FIG. 5A;

FIG. 5C is a front view of the connector body of FIG. 5A;

FIG. 5D is a plan view of the connector body of FIG. 5A;

FIG. 6A is a sleeve, a component of the pipe assembly of FIG. 1;

FIG. 6B is a cross-sectional view of the sleeve of FIG. 6A;

FIG. 7A is a perspective view of an olive, a component of the pipe assembly of FIG. 1;

FIG. 7B is a cross-sectional view of the olive of FIG. 7A;

FIG. 8A is a perspective view of a resilient washer, a component of the pipe assembly of FIG. 1;

FIG. 8B is a cross-sectional view of the resilient washer of FIG. 8A;

FIG. 8C is a close up cross-sectional view of the resilient washer of FIG. 8A;

FIG. 9 is a perspective view of a further aspect of the invention, showing a coupling arrangement, located between a pipe and a connector;

FIG. 10 is a cross-sectional view of the coupling arrangement of FIG. 9; and.

FIG. 11 is a plan view of the coupling arrangement of FIG. 9.

DETAILED DESCRIPTION OF EMBODIMENT(S)

Referring firstly to FIGS. 1 to 3, a connector assembly connecting two pipes in fluid communication is indicated generally at 100. The assembly is suitable for a range of fluids, both liquid and gas, for example oil, foodstuffs and other applications that the skilled person would appreciate. The assembly includes two pipes 102, bridged by a split housing, which is a connector body 110 in this embodiment. The connector body 110 is configured to accept the two pipes 102.

As will be described in more detail below, axial movement of the pipes 102 relative to the connector body 110 is prevented or limited by a mechanical interlock arrangement 104. A mechanical seal arrangement 106 provides a seal between the pipes 102 and the connector body 110. The mechanical seal arrangement 106 includes metallic elements such as, in this embodiment, a sleeve 130 and metal olive 140. In this embodiment, a compressive force is provided on the olive 130, in use, creating a seal between the olive 140 and the sleeve 130.

In this embodiment, each pipe 102 is approximately 100 mm in diameter (i.e. a relatively large diameter pipe suitable for transporting oil, or the like, at high pressure). As shown in FIGS. 4A and 4B, each pipe 102 has a machined portion 108. In this embodiment, the machined portion 108 extends approximately 90 mm in a longitudinal direction from the free end of each pipe. It is generally of a lower external diameter than the remainder of the pipe, e.g. in this embodiment the external diameter of the machine portion is 113 mm, compared to the stock external pipe diameter of 114.8 mm. A groove 109 is provided in each pipe 102. Each groove 109 extends around an entire external circumference of the pipe 102. The grooves 109 are generally rectangular in cross-section and can be formed by any suitable method, such as machining. In this embodiment, the groove 109 is 10.5 mm wide in cross-section, with a 2 mm radius on each corner. The radius enables a corresponding projection to be easily inserted into the groove (described in more detail below). It will be appreciated, however, that each groove 109 may be of any suitable shape in cross-section and may only extend for a partial external circumference of the pipe. The external edge of the free end of each pipe 102 is also chamfered, with a 0.5 mm chamfer in this embodiment. The chamfer helps to break up the edge of the pipe, and can help prevent build up on the edge of the pipes, e.g. in the pipes are being used in applications that are required to be sanitary. The smaller gap can also help to prevent corrosion.

Referring now to FIGS. 5A to 5D, the connector body 110 is in the form of a generally hollow cylinder having opposing open ends. In this embodiment, the pipe connector is approximately 175 mm in length. Although generally a hollow cylinder, the connector body 110 is manufactured in two parts. The connector body 110 is split in two along a horizontal plane A-A extending in the direction of the longitudinal axis of the connector body 110, as illustrated in FIG. 5C. In practice, this means the two halves of the connector body 110 can be brought together in order to surround two pipes 102. The internal surface of the connector body 110 includes a plurality of projections and recesses that help form the mechanical interlock arrangement 104, as well as accommodate the mechanical seal arrangement 106 (described in more detail below).

The connector body 110 is symmetrical across a transverse central axis. Therefore, the connector body 110 will be described starting from one longitudinally outer end, the left end as shown in FIG. 5B.

An outer portion 112 of the connector body 110 includes a front surface 112 a, substantially perpendicular to the longitudinal axis of the connector body 110 in this embodiment, and an external surface 112 b, parallel to the longitudinal axis of the connector body 110, and substantially extending between the two opposing front surfaces 112 a. More specifically, each surface 112 a is connected to the surface 112 b by a radiused corner, a 2 mm radius in this embodiment. The outer portion 112 also has an internal surface 112 c, which is concentric with the external surface 112 b. The connector body 110 can house the two pipes 102 with, at most, a very small clearance. In this embodiment, the external surface 112 b has a bore of between 113 mm and 113.3 mm.

Adjacent the outer portion 112 is an inwardly projecting portion 114. The projecting portion 114 has an internal surface 114 c parallel with the longitudinal axis of the connector body, defining a 109.2 mm bore through this section of the connector body, in this embodiment. The internal surface 114 c is connected to the internal surface 112 c by a radiused corner, with a 2 mm radius in this embodiment. The projecting portion 114 is dimensioned to correspond to the groove 109 provided in each pipe 102, such that the projecting portion 114 fits in the groove 109.

Adjacent the projecting portion 114 is a channel 116. The channel 116 is generally rectangular, in this embodiment, and is intended to accommodate components that contribute to the mechanical seal arrangement 106 (described in more detail below). The channel 116 has a front surface 116 a, that is parallel to the front surface 112 a, and is connected to the internal surface 114 c by a radiused corner, with a 2 mm radius in this embodiment. The front surface 116 a extends outwardly to meet an internal surface 116 c, which is concentric with the external surface 112 b. Adjacent the internal surface 116 c is a rear surface 116 d, which is parallel with the front surface 116 a but extends inwardly to a lesser degree than the surface 116 a. Connecting the front surface 116 a and the internal surface 116 c is a radiused corner, with a radius of 1 mm in this embodiment. Similarly, the internal surface 116 c is connected to the rear surface 116 d with a radiused corner, also with a radius of 1 mm in this embodiment.

The rear surface 116 d defines a front surface of a shoulder 118. The internal surface 118 c is concentric with the external surface 112 b, and defines a bore in this section of 120.5 mm in this embodiment. A rear surface 118 d of the shoulder 118 is parallel with the rear surface 116 d, but extends downwardly from the internal surface 118 c to a lesser amount than the rear surface 116 d extends downwardly from the internal surface 118 c.

Between the two rear surfaces 118 d therefore, a recess 120 is defined. An internal surface 120 c connects the two rear surfaces 118 d to each other, and forms a section with a bore of about 129 mm in this embodiment. The recess 120 is dimensioned such that it can seat the sleeve 130 (described in more detail below).

As shown most clearly in FIG. 5C, the connector body 110 is divided into two halves 110 a, 110 b that can be brought together, and coupled, to surround the pipes 102. As shown in FIG. 5D, each half 110 a, 110 b of the connector body 110 includes a plurality of apertures 122. When the two halves 110 a, 110 b of the connector body 110 are brought together, each aperture 122 on the first half 110 a lines up with a corresponding aperture 122 on the second half 110 b. This arrangement of the apertures defines a plurality of bores 122 a that extend in a direction perpendicular to the plane A-A (shown in FIG. 5C), and also in a direction perpendicular to the flat internal surfaces 123 of each connector body half (shown in FIG. 2).

The bores 122 a extend from the external surface 112 b of the first half of the connector body 110 a to the external surface 112 b of the second half of the connector body 110 b. If a bolt, for example, is placed through the bore 122 a, it can be seen that the first and second halves 110 a, 100 b would be substantially secured from relative movement in a transverse and longitudinal direction.

In this embodiment, when the connector body 110 is viewed in plan as in FIG. 5D, the apertures 122 are distributed longitudinally along the outer peripheries of the connector body halves 110 a, 110 b. In this embodiment, there are eight apertures 122 on the first half 110 a (four on each side), corresponding to eight apertures 122 on the second half 110 b, such that a plurality of bores 122 a are defined through the connector body, as described above.

As can also be seen in FIG. 5C, the apertures 122 are configured differently on the first half of the connector body 110 a than the second half of the connector body 110 b. A planar annular surface 124 is provided that surrounds an opening of the bore 122 a. It will be appreciated that the annular surface 124 may be provided on the first or second halves 110 a, 110 b of the connector body 110. The plane of the annular surface 124 is perpendicular to the direction of the bore 122 a of the aperture 122. It provides a surface to be engaged by a connecting member, e.g. the head of a bolt, when the first and second halves of the connector body 110 a, 110 b are coupled. When viewed in plan, the annular surface 124 is shaped like a cut-off circle, with a circular portion 124 a and a flat edge 124 b. The flat edge 124 b is parallel with the longitudinal axis of the connector body 110 and is adjacent a traverse edge of the connector body 110, when viewed in plan, as in FIG. 5C.

A substantially tear shaped groove 126 is defined around the annular surface 124. The groove 126 follows the profile of the external surface 112 b of the connector body 110, i.e. it curves around the connector body circumferentially. The outline of the groove 126 is a cut-off ellipse, with an elliptical portion 126 a extending from the flat edge 124 b of the annular surface 124. The elliptical portion 126 a of the groove 126 (shown in FIG. 1) connects to the circular portion 124 a of the annular surface 124 by a generally concave internal surface 127. Therefore, it can be seen that a void is defined between the annular surface 124 and the external surface 112 b of the connector body 110. This enables a connecting member, such as a bolt, to be easily inserted by a user during installation. It also enables a bolt head, for example, to sit flush with the annular surface 124 in use, securing the first and second halves of the connector body 110 a, 110 b together strongly.

Distributed evenly on the front surface 112 a, on an appropriate pitch circle, are a plurality of circular apertures 128. The openings of the apertures 128 are flush with the front surface 112 a. The apertures 128 extend longitudinally through the outer portion 112 and the projection 114 to the front surface of the channel 116, creating a plurality of channels 129 through the depth of the outer portion 112 and projection 114 of the connector body 110. In this embodiment, there are ten apertures 128 on each front surface 112 a, but it will be appreciated that any appropriate number of apertures may be provided, for example eight, or twelve.

Seated within the recess 120 of the connector body 110 is the sleeve 130. As shown in FIGS. 6A and 6B, the sleeve 130 is generally a hollow cylinder with opposing end surfaces 132. The sleeve 130 has an internal surface 134 and an external surface 136. The external surface 136 is dimensioned such that the sleeve 130 can fit within the recess 120 with a small clearance, e.g. in this embodiment the longitudinal length of the external surface 136 is 76.8 mm. As can be seen most clearly from FIG. 6B, the end surfaces 132 of the sleeve 130 are made up of a first surface portion 132 a and a second surface portion 132 b. The surface portion 132 a is radial, i.e. it projects in a substantially perpendicular direction to the longitudinal axis of the sleeve 130, and is substantially flat in this embodiment. Connecting the surface portion 132 a to the internal surface 134 is the surface portion 132 b. The surface portion 132 b is angled, having an angle of approximately 12° to the longitudinal axis of the sleeve 130 and 24° inclusive in this embodiment. The angled surface portion 132 b is substantially flat in this embodiment.

Referring to FIGS. 7A and 7B, the olive 140 is composed of two annular portions 140 a and 140 b. The annular portion 140 a is generally rectangular in cross section, i.e. an internal surface 142 and an external surface 143 of the annular portion 140 a are parallel. The annular portion 140 a has a front surface 144 that connects the internal surface 142 and the external surface 143. Projecting in a generally perpendicular direction from the front surface 144 is the annular portion 140 b. The annular portion 140 b is generally tapered. The annular portion 140 b has a smaller external diameter than the annular portion 140 a. The annular portion 140 b has an internal surface 146 that is coplanar to the internal surface 142, such that the two surfaces form a continuous planar surface, creating a constant bore through the olive 140. The annular portion 140 b also has an external surface 147. The external surface 147 is angled, at approximately 10° to the plane of the internal surface 146 and 20° inclusive in this embodiment, to create the taper of the annular portion 140 b. The external surface 147 is generally flat. Connecting the external surface 147 to the external surface 143 is a first rear surface 148 of the olive 140. Connecting the internal surface 146 to the external surface 147 is a second rear surface 149 of the olive 140. The first rear surface 148 and the second rear surface 149 both project in a substantially perpendicular direction to the longitudinal axis of the olive 140. The first rear surface 148 and the second rear surface 149 are both flat surfaces in this embodiment.

In this embodiment, the assembly 100 further includes a resilient washer 150, with an appropriate internal diameter such that a washer 150 fits on each pipe 102 with a very small clearance, e.g. in this embodiment, the internal diameter is 113 mm. Referring now to FIGS. 8A to 8B, the washer 150 is a spring washer. The washer 150 is annular, with a generally ‘b/p shaped’ cross section. It has a front surface 152 and a rear surface 154. The front surface 152 and the rear surface 154 are connected by two substantially curved transitions. At the radially outer edge of the washer 150, the front surface 152 is connected to the rear surface 154 by a first curved transition 158 that defines the outer diameter of the washer. Looking in cross-section, the curved transition 156 is made up of a flat surface 156 b, and two curved surfaces, 156 a and 156 c. The flat surface 156 b is perpendicular to the front surface 152 and the rear surface 154. The flat surface 156 b is 1 mm long in this embodiment. Connecting the flat surface 156 b to the front surface 152 is the curved surface 156 a. Connecting the flat surface 156 b to the rear surface 154 is the curved surface 156 c. The curved surfaces 156 a and 156 c are both convex, and have a radius of 0.5 mm in this embodiment. At the radially inner edge of the washer 150, the front surface 152 is connected to the rear surface 154 by a second curved transition 158 that defines the inner diameter of the washer. Looking in cross-section, the curved transition 158 is made up of two flat surfaces, 158 b and 158 d, and four curved surfaces 158 a, 158 c, 158 e, and 158 f. The flat surface 158 b is perpendicular to the front surface 152 and the rear surface 154. The flat surface 158 b is 0.2 mm long in this embodiment. The flat surface 158 d is parallel to the front surface 152 and the rear surface 154. The flat surface 158 d is 1.2 mm long in this embodiment. Connecting the flat surface 158 b to the front surface 152 is the curved surface 158 a. Connecting the flat surface 158 b to the flat surface 158 d is the curved surface 158 c. The curved surfaces 158 a and 158 c are both convex, and have a radius of 1.9 mm in this embodiment. Connecting the flat surface 158 d to the rear surface 154 are two curved surfaces, 158 e and 158 f. The curved surface 158 e is adjacent the flat surface 158 d and is convex, with a radius of 1.5 mm in this embodiment. The curved surface 158 f is adjacent the rear surface 154 and is convex, with a radius of 0.5 mm in this embodiment. The washer 150 is typically made of metal, such as steel. Preferably a sprung steel will be used, with a high yield strength and high elastic modulus, such as medium/high carbon-steel, but any suitable material can be used. It will also be appreciated that any suitable type of resilient washer may be used. It will be appreciated that the ‘springiness’ shape is a function of both the described geometrical shape of the washer and the material the washer is made from.

To assemble the components of the assembly 100, firstly the free end of each pipe 102 is machined to form the machined portions 108, and the grooves 109 in the appropriate places on the pipes 102. Then, taking each pipe 102 individually, the washer 150 is slid on to the free end of the pipe 102. The olive 140 is then slid on to the free end of the pipe 102. The sleeve 130 is slid on to the pipe 102 next. At this point, the two pipes 102 are brought together, such that the sleeve 130 bridges the gap between the pipes.

The two halves 110 a, 110 b of the connector body 110 are brought around the pipes 102, the sleeve 130, the olives 140, and the washer 150. The projections 114 of the connector body 110 correspond with the grooves 109, so engage the grooves 109 of the pipes 102, to prevent or limit axial movement of the connector body 110 relative to the free end of the pipes 102. The washer 150 and the olive 140 are accommodated within the channel 116. The washer 150 is dimensioned to have an internal diameter similar to the external diameter of the pipe 102 and an external diameter similar to the bore of the internal surface 116 c. Therefore, the washer 150 fits in the channel 116 and contacts the front surface 116 a of the channel 116. The front surface 144 of the annular portion 140 a of the olive 140 contacts the washer 150. The washer 150 is arranged such that the curved transition 158 of the washer 150 abuts the front surface 144 of the olive 140 in use. This enables the washer to deflect to sustain any force that is applied and substantially limit the movement of the olive 140.

To couple the first and second halves 110 a, 110 b of the connector body 110, connecting members are threaded through the apertures 122. For example, a plurality of threaded bolts (not shown) could be used. The body of the bolt will pass through the void created by the groove 126, and the bore 122 a, of the aperture 122 and the head of the bolt will engage the annular surface 124. The body of the bolt will protrude from the opposing open end of the aperture 122 where a nut can be threaded on the body of the bolt. This substantially secures the first and second halves 110 a, 110 b of the connector body from relative movement in a transverse or longitudinal direction.

A plurality of bolts (not shown) are then inserted through the apertures 128 from the front surface 112 a in the direction of the channel 116 of the connector body 110. They pass through the channels 129 and contact the washer 150, which is located adjacent the openings of the channels 129 in the surface 116 a, as shown most clearly in FIG. 3. The bolts may have an external thread and the channels 129 may have an internal thread. As the bolts are tightened, a force is therefore applied to the washer 150 and is transferred to the olive 140. The washer 150 advantageously ensures that the force applied is maintained in use, as it can account for any natural ‘flex’ that may occur, as well as any decrease in the force applied by bolts over time, or if they loosen in use. It also protects the olive 140 from abrasive damage from the bolts.

The force applied by the bolts acts on the olive 140 in the direction of the sleeve 130. Specifically, the angled surface 147 of the olive 140 engages the angled surface 132 b of the sleeve 130. The angled surfaces interface and the olive 140 conforms to the greater angle of the surface 132 b of the sleeve 130. This creates a strong mechanical seal between the sleeve 130 and the olive 140.

Therefore, in use, oil can pass from one pipe 102 to another pipe 102 under high pressure with a very low risk of leakage due to the strong mechanical seal created by the assembly 100.

Referring now to FIGS. 9 and 10, a coupling arrangement is indicated generally at 200. The coupling arrangement 200 utilises the same mechanical seal arrangement 206 as described for the previous embodiments, except the connector body (110 of the previous embodiment) is now a connector 210 having a female open end configured to receive a male free end of a pipe 202. The connector 210 can be any type of connector that is configured to receive a pipe, such as a general pipe joint, a flexible connection, a valve, or a pipe reducer. The skilled person will appreciate any other appropriate applications of the coupling arrangement 200.

The connector 210 has an open end that receives the pipe 202. The pipe 202 includes a circumferential groove 209. In this embodiment the connector 210 has a radial internal surface 212 that engages the free end of the pipe 202. The radial internal surface 212 provides a stop for the pipe 202 when it is inserted into the open end of the connector 210 during assembly of the coupling arrangement 200.

The connector 210 also includes an internal angled surface 214. The angled surface 214 is equivalent to the surface portion 132 b of the first embodiment, and is intended to engage a corresponding angled surface of an olive 250 to create a metal-to-metal seal (described in more detail below). The angled surface 214 has an angle of approximately 12° to the longitudinal axis of the connector 210, and 24° inclusive in this embodiment.

The connector 210 also includes a circumferential groove 216, with dimensions that are equivalent to the groove 209 of the pipe 202.

Axial movement of the connector 210 relative to the pipe 202 is substantially prevented or limited by a mechanical interlock arrangement. In this embodiment, a cap 230 encircles a portion of the pipe 202 and the connector 210 to help prevent separation of the pipe 202 and the connector 210 in use. As shown most clearly in FIG. 10, the cap 230 has a constant external diameter but a varying internal diameter such that three portions of the cap are defined. Starting from the left in FIG. 10, the first portion 230 a has an internal diameter substantially equal to the external diameter of the pipe 202 such that the cap fits over the pipe 202 with a small clearance. The second portion 230 b has a greater internal diameter 230 b such that a cavity 232 is defined between the external surface of the pipe 202 and the internal surface of the second cap portion 230 b. The cavity 232 is dimensioned such that it can house an olive 240 and a washer 250 of the mechanical seal arrangement 206 (described in more detail below). The third portion 230 c has an internal diameter substantially equal to the external diameter of the connector 210 such that the cap 230 fits over the connector 210 with a small clearance.

A circumferential projection 234 projects from the internal surface of the first cap portion 230 a. The projection 234 corresponds to the groove 209 in the pipe 202, such that the projection 234 and the groove 209 engage in use, substantially preventing relative axial movement. A circumferential projection 236 also projects from the internal surface of the third cap portion 230 c. The projection 236 corresponds to the groove 216 in the connector 210, such that the projection 236 and the groove 216 engage in use, substantially preventing relative axial movement. It will be appreciated that other methods of substantially preventing relative axial movement could be used. For example, corresponding threaded surfaces could be provided, e.g. such that the cap is ‘screwed’ on during assembly. A front surface 238 of the cap 230 includes a plurality of apertures 239 that pass through the entire depth of the first cap portion 230 a, from the front surface 238 to the cavity 232, such that openings are provided into the cavity 232 that are substantially adjacent the olive 240 and the washer 250 in use. The apertures 239 are equivalent to the circular apertures 128 of the first embodiment, and will be not be described in any more detail.

The cap 230 is split in two halves along a horizontal plane (not shown in Figures), equivalent to the split of the connector body 110 of the first embodiment. This enables the two halves of the cap 230 to be brought together to encircle a portion of the pipe 202 and a portion of the connector 210 during assembly of the coupling arrangement 200. It can be seen from FIG. 11 that a plurality of apertures 233 are included in the external surface of the cap 230 to enable the two halves of the cap 230 to be secured together in an equivalent way to how the two halves of the connector body 110 are secured together in the first embodiment.

The olive 240 and washer 250 are as described in the first embodiment herein.

To assemble the coupling arrangement 200, the grooves 209, 216 are made in the pipe 202 and the connector 210 respectively. The pipe 202 is then slid inside the open end of the connector 210 such that the free end of the pipe 202 engages the radial internal surface 212 of the connector 210. The olive 240 is then slid on to the pipe 202, such that the angled surface of the tapered portion of the olive 240 engages the angled surface 214 of the connector 210. The washer 250 is then slid on to the pipe 202. The two halves of the cap 230 are brought together around the pipe 202 and the connector 210, and connecting members are threaded through the apertures 233. The projections 234, 236 engage the grooves 209, 216 respectively. The olive 240 and the washer 250 are received within the cavity 232 of the cap 230.

A plurality of bolts (not shown) are then inserted through the apertures 239 from the front surface 238 in the direction of the cavity 232 of the cap 230. They pass through channels in the first cap portion 230 a and contact the washer 250, which is located adjacent the openings in a front surface 232 a of the cavity. The bolts may have an external thread and the channels may have an internal thread. As the bolts are tightened, a force is therefore applied to the washer 250 and is transferred to the olive 240.

The force applied by the bolts acts on the olive 240 in the direction of the connector 210. Specifically, an angled surface 247 of the olive 240 engages the angled surface 214 of the connector 210. The angled surfaces interface and the olive 240 conforms to the greater angle of the surface 214 of the connector 210. This creates a strong mechanical seal between the connector 210 and the olive 240.

Therefore, in use, fluid can pass from the pipe 202 to the connector 210 under high pressure with a very low risk of leakage due to the strong mechanical seal created by the coupling assembly 200.

Although the invention has been described above with reference to one or more preferred embodiments, it will be appreciated that various changes or modifications may be made without departing from the scope of the invention as defined in the appended claims. 

1. An apparatus for connecting two pipes in fluid communication, the apparatus comprising: a connector body configured to, in use, bridge a first and a second pipe, each pipe having a free end; a mechanical interlock arrangement, for preventing or limiting axial movement of the connector body relative to the free ends of the first and second pipes; and a mechanical seal arrangement for providing a metal-to-metal seal between the pipes and the connector body.
 2. The apparatus of claim 1 wherein the mechanical seal arrangement includes a first metallic element configured to fit on a free end of a pipe.
 3. The apparatus of claim 2 wherein the first metallic element is specifically dimensioned to fit on a pipe to ensure the mechanical seal arrangement can create a strong seal, in combination with the connector body.
 4. The apparatus of claim 3 wherein the mechanical seal arrangement further includes a second metallic element, configured to be located between the first metallic element and an internal surface of the connector body, such that the seal is created between the first and second metallic elements.
 5. The apparatus of claim 4 wherein the first metallic element is an olive having a tapered portion comprising an angled surface, arranged to contact a corresponding angled surface of the second metallic element.
 6. The apparatus of claim 5 wherein the two angled surfaces have different angles.
 7. The apparatus of claim 4 wherein the second metallic element is a sleeve, configured to encircle the two free ends of the pipes, in use.
 8. The apparatus of claim 2 further comprising a mechanism for applying a force to the first metallic element, in order to assure a seal between a pipe and the connector body.
 9. The apparatus of claim 2 wherein the connector body comprises one or more apertures defining a plurality of channels through a portion of the connector body, from a front surface of the connector body to a radial internal surface, the radial internal surface being located substantially adjacent the first metallic element in use.
 10. The apparatus of claim 9 wherein each channel comprises an internal thread such that a bolt, with a corresponding external thread, can be rotatably inserted into each channel to provide a force that acts on the first metallic element in an axial direction.
 11. The apparatus of claim 2 wherein the mechanical seal arrangement further comprises a resilient washer arranged for sustaining the force applied on the first metallic element.
 12. The apparatus of claim 9 wherein the washer is configured to be located between the radial internal surface of the connector body comprising the apertures, and the first metallic element.
 13. The apparatus of claim 1 wherein the mechanical interlock arrangement comprises at least one projection on an internal surface of the connector body.
 14. The apparatus of claim 13 wherein one or both of the projections on the connector body and the groove on the pipe are circumferential.
 15. The apparatus of claim 1 wherein the connector body is provided as separate first and second parts, such that they can be brought together around the pipes, in use.
 16. The apparatus of claim 15 wherein the connector body is split along a horizontal plane to define the first and second parts.
 17. The apparatus of claim 16 wherein the first and second parts of the connector body comprise bores extending in a direction perpendicular to the horizontal plane, configured to accept connecting components, in order to couple the first and second parts of the connector body to each other.
 18. The apparatus of claim 17 wherein each bore comprises an annular surface with a plane parallel to the horizontal plane, configured to be engaged by a connecting component in use.
 19. A pipe assembly connecting two pipes in fluid communication, the assembly comprising: two pipes, each having a free end; a connector body bridging the pipes; and a mechanical seal arrangement for providing a metal-to-metal seal between each pipe and the connector body.
 20. The pipe assembly of claim 19 wherein the mechanical seal arrangement comprises a first metallic element and a second metallic element, the first and second metallic elements arranged to engage each other to create the metal-to-metal seal.
 21. The pipe assembly of claim 20 wherein the first metallic element is an olive having a tapered portion comprising an angled surface, arranged to contact a corresponding angled surface of the second metallic element.
 22. The pipe assembly of claim 21 wherein the two angled surfaces have slightly different angles.
 23. The pipe assembly of claim 20 wherein the second metallic element is a sleeve, configured to fit within the connector body and encircle the two free ends of the pipes.
 24. The pipe assembly of claim 20 wherein the assembly further comprises a mechanism arranged to act on the first metallic element, applying a force, to induce axial movement of the first metallic element in the direction of the second metallic element.
 25. The pipe assembly of claim 19 wherein the connector body comprises one or more apertures defining channels through a portion of the connector body, from a front surface of the connector body to a radial internal surface substantially adjacent the first metallic element.
 26. The pipe assembly of claim 20 further comprising a resilient washer, located between the connector body and the first metallic element, to assure the force applied on the first metallic element in use.
 27. The pipe assembly of claim 19 further comprising a mechanical interlock arrangement.
 28. The pipe assembly of claim 27 wherein the mechanical interlock arrangement comprises at least one projection on an internal surface of the connector body.
 29. The pipe assembly of claim 28 wherein one or both of the projections on the connector body and the groove on the pipe are circumferential.
 30. The pipe assembly of claim 19 wherein the connector body is provided as separate first and second parts, the first and second parts having been brought together around the pipes.
 31. The pipe assembly of claim 30 wherein the connector body is split along a horizontal plane to define the first and second parts.
 32. The pipe assembly of claim 31 wherein the first and second parts of the connector body comprise bores extending in a direction perpendicular to the horizontal plane, configured to accept connecting components, in order to couple the first and second parts of the connector body to each other.
 33. The pipe assembly of claim 32 wherein each bore comprises an annular surface with a plane parallel to the horizontal plane, configured to be engaged by a connecting component in use.
 34. A method of connecting two pipes in fluid communication, the method comprising: providing two pipes, each pipe having a free end; locating a first part of a metal-to-metal seal arrangement on the free end of each pipe; and locating each free end of the pipe within a connector body having a second part of a metal-to-metal seal arrangement, such that the connector body bridges the two pipes, wherein the first and second metal-to-metal seal arrangements provide a metal-to-metal seal between a respective pipe and the connector body.
 35. The method of connecting two pipes according to claim 34 comprising applying a force to the first part of the seal arrangement, in order to assure a seal between the pipe and the connector body.
 36. The method of connecting two pipes according to claim 34 comprising providing a mechanical interlock arrangement, for preventing or limiting axial movement of the connector body relative to the pipes.
 37. The method of connecting two pipes according to claim 36 wherein the mechanical interlock arrangement comprises forming a groove on an outside surface of at least one pipe and providing a projection on an internal surface of the connector body, and engaging the projection with the groove to prevent or limit axial movement of the connector body relative to the pipes.
 38. The method of connecting two pipes according to claim 34 further comprising providing a resilient washer between the connector body and the first part of the seal arrangement, for applying a force to the seal element.
 39. (canceled) 